On Friday, December 30, 2016 07:05 PM Brian Andrus wrote: > We have a set it and forget it cronjob setup once an hour to keep things a bit more balanced. > > 1 * * * * /bin/bash /home/briana/reweight_osd.sh 2>&1 | /usr/bin/logger -t ceph_reweight > > The script checks and makes sure cluster health is OK and no other rebalancing is going on. It will > also check the reported STDDEV from `ceph osd df` and if outside acceptable ranges executes a > gentle reweight. Would you mind sharing that script? > The three parameters after the reweight-by-utilization are not well documented, but they are > > 103 - Select OSDs that are 3% above the average (default is 120 but we want a larger pool of OSDs to choose from to get an eventual tighter tolerance) > .010 - don't reweight any OSD more than this increment (keeps the impact low) > 10 - number of OSDs to select (to keep impact manageable) Ah! Thank you for that pointer. For the record the same arguments can be used for dry-runs of "ceph osd test-reweight-by-utilization ..." and correspond to these values in the output from test-reweight-by-utilization: oload 120 max_change 0.05 max_change_osds 4 The above values are the current defaults in Hammer (0.94.9), but can easily be changed to see the impact before running the actual rebalance.. Regards, Jens Dueholm Christensen _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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